Chronic Expanding Haematomas with Interesting Presentations

Abstract

The unusual presentation of our two cases posed a diagnostic dilemma between a chronic expanding haematoma and soft tissue sarcoma even after all investigations and biopsy reports were complete. Salient points to differentiate between the two are discussed along with literature review.

INTRODUCTION

Chronic expanding haematomas are tumour like lesions with a vague history of trauma and has been mentioned infrequently in literatures with a variety of presentations.^1,2,3 They usually lay dormant for many months before suddenly starting to expand in a mode very similar to that of a chronic subdural haematoma. The importance of these swellings lies in its mimicry of soft tissue sarcomas. We present two such cases where the aggressive nature of the swelling and unusual presentation posed a diagnostic dilemma to the treating surgeon in spite of all investigations. Both patients underwent complete excision of the swelling with excellent results. Salient points to differentiate between the two are discussed along with literature review.

CASE REPORT

Case 1

A 61-year-old gentleman presented with a sudden increase in size of an already existing swelling over the mid third of right leg associated with throbbing pain of 4 months duration. He had noticed a mild swelling at the above mentioned site for the past 11 years following an RTA when he fractured his tibia but chose to ignore it until now. There was no recent history of trauma or any bleeding abnormalities. Clinically the swelling was tense shiny and tender with engorged veins and diffuse margins associated with complete foot drop but involving only the deep peroneal component of the common peroneal nerve (Figure 1). X-rays showed some calcifications within the substance of the swelling and an urgent MRI scan revealed a well encapsulated mass between the peroneal muscles mechanically compressing the deep peroneal nerve (Figure 2). A trucut biopsy showed cholesterol clefts along with RBC's (Figure 3) haemosiderin pigmentation and areas of dystrophic calcification suggestive of a chronic haematoma. The patient successfully underwent enucleation of the swelling (Figures 4A, 4B) along with cutaneofascial suture to obliterate the dead space. Cut section revealed thick chocolate coloured fluid characteristic of the fluid found in an expanding chronic subdural haematoma. His foot drop started to recover within 2 weeks of surgery and had completely recovered by the 4th month of follow up.

Figure 1.

Swelling with engorged veins and right sided foot drop.

Figure 2.

Coronal and axial MRI sections showing the well encapsulated swelling.

Figure 3.

Biopsy findings showing the characteristic picture of chronic haematoma with cholesterol clefts and RBCs.

Figure 4A, 4B.

Swelling excised in toto.

Case 2

A 22-year-old gentleman presented with pain and sudden increase in size of an already existing swelling over the dorsum of right foot of 3 months duration. He had a cystic swelling measuring 0.5 by 0.5 cm at the same site since 1999 following a football injury which did not bother him until now when the pain worsened and the swelling suddenly increased in size with no apparent trauma. Clinical and MRI findings (Figure 5) revealed a tender 4 by 4 cm tensely cystic swelling in the subcutaneous tissue on the dorsolateral hind foot with engorged veins and well defined margins. The MRI showed a mass of high signal intensity on the T1 weighted sequence with appearances consistent with haematoma and showed no post contrast enhancement. Trucut biopsy confirmed the swelling as a haematoma. The patient successfully underwent complete excision of the swelling with no recurrence at 6 months follow up.

Figure 5.

MRI images of the foot haematoma.

DISCUSSION

Reid et al.¹ first used the term chronic expanding haematoma for haematomas that persisted and increased in size more than a month after the initiating haemorrhage. The cause of initial haemorrhage^4,5 is most commonly trauma which results in displacement of skin and subcutaneous fatty tissue from more deeply located fixed fascia with formation of blood filled cysts. Normally the haematoma gets completely absorbed but if it is large, the blood may not be completely resorbed in which case it becomes encapsulated by a fibrous wall forming a chronic swelling.

Rarely, these swellings slowly expand^3,6 and can be mistaken for a soft tissue malignancy. Most expanding haematomas have been reported in the thigh,^5,7 while the calf is a less common location.^1,8 These swellings have marked similarities with subdural haematomas, pseudo tumours in haemophiliacs, and rectus sheath haematomas^1,3 in that they all have the potential to expand at anytime during an individual's life.

Various theories have been put forth to explain the cause of sudden expansion. One such theory is that a high osmotic pressure gradient is produced by the breakdown products of the haematoma, resulting in a localized inflammatory reaction.^9,10,11 Factors in the coagulation cascade along with release of vasoactive substances are believed to be associated with an inflammatory reaction which may cause additional bleeding from fragile capillaries. This additional bleeding contributes to a perpetual cycle of inflammation.^2,9

Macroscopically chronic haematomas have a peripheral wall of dense fibrous tissue and a central space containing fresh and altered blood. Histologically^{1, 3} there is an outer zone of dense collagenous tissue with deposits of hemosiderin, a middle zone of eosinophilic amorphous material, and an inner zone of granulation tissue overlain by RBCs and fibrin into which new capillaries grow. Areas of dystrophic calcification associated with reactive inflammatory changes are also seen.

In 1997, Mentzel et al.^7,12 noted that the above mentioned histological features are similar to conditions previously described as calcific myonecrosis, chronic expanding haematoma, or post traumatic cyst of soft tissues. He grouped these processes together, calling them ancient haematoma. The importance of ancient haematomas lies in their clinical, and sometimes histologic mimicry of soft tissue sarcomas.

An X-ray and biochemical tests are always essential to rule out any fracture or bony mass, but MRI^13,14 is the gold standard when evaluating these swellings. On MRI, chronic expanding haematomas exhibit heterogeneous signal intensity. They display high-signal central zones of fluid collection and a peripheral low-signal rim of fibrocollagenous tissue. A blood pooling study can sometimes demonstrate the “Halo Sign” of an encapsulated haematoma.¹⁵ Biopsy is the only way to rule out a malignant tumour.

Although the MRI and biopsy results in both of these cases were reassuring, the clinical scenario of sudden foot drop, increasing pain, and expanding mass pointed more toward a malignant process rather than a benign condition. Several salient features allow differentiation between sarcomas and chronic expanding haematomas. Sarcomas typically have no history of trauma, have shorter duration of symptoms and usually involve the deeper structures. It should also be noted that some soft tissue sarcomas can reveal haemorrhagic or cystic changes.

Included within the differential diagnosis are myositis ossificans and tumoral calcinosis.¹⁶ Myositis does not manifest as a chronic expanding mass and histology shows a characteristic zoning phenomenon. Tumoral calcinosis is seen frequently in the vicinity of large joints and shows florid histiocytic proliferation with osteoclast like giant cells and lymphocytes on histology.

Management of chronic haematomas includes simple analgesics and anti inflammatories, aspiration, or incision and drainage.⁴ Surgical excision (including the fibrous pseudocapsule) along with cutaneofascial suture to obliterate the dead space is the treatment of choice4 in cases of large haematomas. Aspiration of the fluid or incomplete excision could lead to recurrence, continued growth, or a chronic draining sinus with or without infection.^6,7,16 Both of our cases underwent complete excision with excellent results. The first patient had complete recovery from foot drop by the 4th month of follow-up, while the second case had no recurrence at the 6th month of follow up.

In summary, it is difficult to differentiate between a chronic expanding haematoma and soft tissue sarcoma based upon clinical findings alone. X-ray and biochemical tests are frequently indicated to rule out a fracture or bony mass, but MRI is the gold standard of non-invasive evaluation. A biopsy is the only way to definitively rule out malignancy, while the treatment of choice is surgical excision and cutaneofascial suture.